From 2651c4ce26835c0da15bfa5221df83d02743f2a2 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 6 Aug 2018 18:54:31 +0200
Subject: [PATCH] rec: Replace the cached qname at once instead of label by
 label

(cherry picked from commit 119f9dc913c1c088a8323cd1345744a7a91c89f9)
---
 pdns/recpacketcache.cc | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/pdns/recpacketcache.cc b/pdns/recpacketcache.cc
index 5b1feeca28..6faf00ae64 100644
--- a/pdns/recpacketcache.cc
+++ b/pdns/recpacketcache.cc
@@ -67,14 +67,9 @@ bool RecursorPacketCache::checkResponseMatches(std::pair<packetCache_t::index<Ha
       responsePacket->replace(0, 2, queryPacket.c_str(), 2);
       *valState = iter->d_vstate;
     
-      string::size_type i=sizeof(dnsheader);
-      
-      for(;;) {
-        unsigned int labellen = (unsigned char)queryPacket[i];
-        if(!labellen || i + labellen > responsePacket->size()) break;
-        i++;
-        responsePacket->replace(i, labellen, queryPacket, i, labellen);
-        i = i + labellen;
+      const size_t wirelength = qname.wirelength();
+      if (responsePacket->size() > (sizeof(dnsheader) + wirelength)) {
+        responsePacket->replace(sizeof(dnsheader), wirelength, queryPacket, sizeof(dnsheader), wirelength);
       }
 
       d_hits++;
-- 
2.47.2